1. Field of the Invention
This invention relates to the neck finish (i.e., cross-sectional shape) of containers formed of relatively rigid materials such as polyvinyl chloride. Such neck finishes are formed to cooperate with standard push-on caps which were initially designed for use with less rigid materials such as polyolefins.
2. Prior Art
Caps used with the neck finish of this invention such as those shown in U.S. Pat. Nos. 4,676,389 and 4,484,687 as well as many variations thereof. Such caps have a top disk from which depends a substantially cylindrical outer skirt having at least one locking bead on the inside surface thereof. The neck to which the present invention relates is formed on the exterior with locking beads which mate with locking beads on the cap. Many of these caps have tamper-evident features whereby the portion of the skirt carrying the lower locking bead is torn away, leaving a reclosure cap which may be pried off the neck and used to reseal the remaining contents of the container. Some of the caps used with the neck finish have an inner skirt or plug which fits the inside of the neck.
Prior art containers for the most part have been made from relatively flexible materials such as polyolefins. Their lips having relatively sharp inner and outer peripheral corners. The outer corner engages the interior of the outer skirt of the cap promoting distortion of the skirt outwardly particularly when the cap is being used as a reclosure cap. The pliable polyolefin containers do not deform to the extent that the distortion of the closure becomes excessive.
The present invention overcomes some of the problems which occur when the less rigid polyolefin containers are replaced with more rigid containers.